Gas turbine engines are used extensively in high performance aircraft and they employ compressors, combustors and turbines and during operation they generate energies and air flows that impact the performance of the engine's systems. Often those energies and air flows impart forces upon various components of the engine and if properly channeled greater efficiencies and economical performance can be achieved which is desired in the competitive airline industry. However, some of those energies may induce premature or undesirable wear on the engine's components which in turn can negatively impact operating performance and efficiencies of the engine.
Combustors are employed in gas turbine engines to ignite fuel and air mixtures. Typical combustors may use inner and outer liners that define an annular combustion chamber in which the fuel and air mixtures are combusted. The inner and outer liners are spaced radially inwardly from the combustor casing such that inner and outer passage ways are defined between the respective inner and outer liners and the combustor casing. One or more fuel igniters may extend through the combustor casing and the outer passageways, and are coupled to the outer liner by igniter tubes that are attached to the combustor liner. The fuel igniter tubes serve to secure and maintain the igniters in alignment relative to the combustor chamber as well as provide a sealing interface for the igniter between the outer passageway and the combustion chamber.
Combustor assemblies are subjected to extreme forces during ignition and during normal operation. Certain combustor components of the igniters, such as the igniter ferrule and cap, are subjected to significant wear during operation of the engine. Such conditions include engine vibrations which in turn results in a relative sliding motion between the igniter tube and the ferrule, resulting in wear between the captive ferrule and a tube plateau. Such action consequently may prematurely reduce the life of the igniter tube. This is in part due to the relatively small surface area of contact between the ferrule and the igniter tube which during operation can result in excessive wear rates of the igniter tube. Such a condition remains an engineering challenge in the aircraft industry.
An exemplary embodiment for an improved igniter assembly is provided that is used in connection with a gas turbine engine. Enhanced wear characteristics and increased wear life of the igniter tube assembly is achieved while maintaining the envelope in which the igniter assembly resides. An exemplary method of assembling an igniter tube assembly for an engine is further provided.